| Class | Class Ia antiarrhythmic |
|---|---|
| Chemistry |
Aminobenzamide |
| Routes of administration |
Oral and IV |
| Absorption |
Oral bioavailability = 75-95% |
| Solubility |
Highly water soluble; pKa 9.32 |
| Distribution |
VOD = 1.5-2.5L/kg; only 15-25% protein bound |
| Metabolism |
Hepatic metabolism of some variable fraction, into active metabolites (NAPA) |
| Elimination |
Half-life 3-4 hours; a significant proportion of the drug is excreted unchanged in the urine |
| Time course of action |
Duration of action is similar to half-life of the drug and its metabolites, ~ 4-8 hrs |
| Target receptor |
Nav1.5 subunit of the fast voltage-gated sodium channels |
| Mechanism of action |
Acts by blocking voltage-gated sodium channels and potassium channels, thereby decreasing the slope of Phase 0 and increasing the duration of the cardiac action potential |
| Clinical effects |
Antiarrhythmic effect, prolongation of QRS, prolongation of QT interval |
| Literature reference |
Giardina (1984) |
| CICM details of understanding | Not specifically listed in the CICM syllabus |
| Mentioned around Deranged Physiology | |
| Related SAQs |